Phthalocyanines have been widely used as pigments, and above all, naphthalocyanine compounds have been much studied for near-IR dyes not substantially absorbing visible light but absorbing IR rays (e.g., JP-A-2-296885).
Various types of naphthalocyanine compounds are known, having a substituent on the naphthalene ring of the naphthalocyanine skeleton thereof. Concretely known are those having, as the substituent on the naphthalene ring thereof, a halogen atom, an alkyl group, an aryl group, a hydroxyl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an amino group, an alkylamino group, an oxycarbonyl group, an alkoxycarbonyl group, a cyano group, a nitro group (e.g., JP-A-2-296885, Journal of Chemical Society, Parkin Transaction, I, pp. 2453-2458 (1988)); those having an acrylamide group as a polymerization precursor (e.g., JP-A-7-118723); and those having an acylamino group or its precursor (e.g., JP-A-11-152413, JP-A-11-152414 and JP-A-11-152415). Also known are copper naphthalocyanine compounds having a specific alkoxyethyl group on the naphthalene group thereof (e.g., JP-A-2000-147824). However, for image-forming materials, IR-sensitive thermal recording materials, optical recording elements and optical film materials, it is desired to develop naphthalocyanine compounds capable of expressing more excellent capabilities.